Art of bonding metal to insulation



June 4, '1940. w OSENBERG 2,203,100

ART 0F BONDING METAL TO INSULATION Filed Dec. 24, 1937 2 sheets-sheet 1F 4 f-gg? /Q'. Erw L1 E' n Bam Y ft 5g FEM f W L.,

June 4, 1940. w .QSENBERG 2,293,100

ART OF BONDING METAL T0 INSULATIQN Filed Dec. 24, 1937 2 sheets-sheet 2Patented June 4, 1940 UNITED STATES PATENT OFFICE 2,203,100 ART-FBONDING METAL TO INSULATION Werner Osenberg, Dresden, GermanyApplication December 24, 1937, Serial No. 181,661 i 8 Claims. (Cl.l219--3) The present invention is especially concerned with theattachment ofmetallic bodies to carriers, more particularly in the caseof electrical apparatus such as contact assemblies, lamp V sockets,sockets for radio tubes or similar apparatus used in radio or the like,and especially where the conducting part is to be fastened to anon-conducting carrier of ceramic material or the like. v

For a clearer understanding of the invention it -may be noted thatvwhere a Contact piece of conducting material is tc be attached to acarrier of ceramic material which is to be introduced in the usualoutlet, the extension of the prong f.

may be introduced through the ceramic carrier and the attachmenteffected by means of a nut upon the threaded extremity thereof. Therequisite pressure in tightening the nut in practice frequently injuresthe ceramic carrier which as a y result of the application of. pressuremay develop cracks or actually break in two.

If the extension of the contact prong is cemented into a bore in theceramic carrier a permanently useful connection between the carrier andthe prong is not to be depended on because in practice the cement willnot hold and the greatly that as a result of expansion the same4 willcrack or` break.

According to the present invention a satisfactory connection isaccomplished without strain upon or excessive' heating of. the ceramicmaterial,

d0v by performing the securing operation by the application of heatelectrically 'with the aid of appropriate electrodes.

According to the present invention the ceramic carrier is provided withconformationswith which a portion of the surface area of thesheet metalpiece is intimately connected by resort to electrodes applied adjacentsuch conformation to cause the metal to soften at that region and to besnugly engaged with said conformation either by the pressure exerted bythe electrodes or by resort to a separate pressure die applied at theheat softened portion. In a specic application the carrier may beprovided with a projection of appropriate form, illustratively of atenon shape and the electrodes of appropriate form applied to the sheetmetal adjacent the sides of the tenon to cause the metal therebetween tobecome softened and to become readily shaped to the contour of theprojection for snug engagement therewith, rendered especially secure by5 the contraction of the metalin cooling. For localization of the heatgenerated by the electrodes, the sheet metal might be slotted to form anarrow bridge between the electrodes at which the heat and softeningeffect are localized. 1o Where the insulating element is in the form ofa cylinder and the metal element in the form of a cap to be appliedthereto, the cylinder might be provided with peripheral grooves and theelectrodes applied to soften the cap metal therel5 'adjacent either toform a bead or a multiplicity of depressions forced into the groove orthe rim of the cap might be turned into such grooves.

In the accompanying .drawings in which are shown one or more'of thevarious possible em- 2o bod'unents of the several features of theinvention,

Fig.' l is a view in longitudinal cross-section showing the method ofattaching thin sheet metal to a.ceramic or other insulating surface, 25

Fig. 2 shows the finished assembly prepared according to the embodimentof Fig. 1,

Fig. 3 is a view similar to Fig.- l of a modication, i

Fig. 4 shows ai. alternative method of forming 30 the embodiment; ofFig-.1,

Fig. 5 is a view like Fig. 4 of a further alternative,

Fig. 6 is a fragmentary sectional view similar to Fig. 3, showinganother embodiment, 35

Fig. 7 shows an alternative form of. pressure roll used in carrying outthe process indicated in Fig. 6,

Fig. 8 is a View similar to Fig. 7 of a further alternative, 40

Fig. 9 shows a fragmentary perspective view of` electrodes for producinganother embodiment,

` Fig. 10 is a View in longitudinal cross-section showing the productformedby the apparatus of Fig. 9,

Fig'. l1 is a view partly in section of an alternative embodiment of.electrodes in association with the sheet metal,

Fig. 12 shows the product produced by the embodiment of Fig. 11, 50

Fig-13 is aview in longitudinal cross-section through the electrodearrangement of Fig. 1l,

Fig. 14 is a view in transverse cross-section of a modied projection onthe ceramic or other insulating holder,

Fig. 15 is a plan View thereof,

Fig. 16 is a modification of the embodiment of Fig. 14,

Fig. 17 is a plan view thereof,

Fig. 18 is a view in longitudinal'cross-section of another embodiment ofceramic and sheet metal assemblage,

Fig. 19 is a side elevation illustrating another application of theprocess,

' Fig. 20 is a plan View thereof,

Fig. 21 is' a IView in longitudinal cross-section taken on line 2I-2i ofFig. 22, illustrating a method of applying a sheet metal cap to acylindrical carrier,

Fig. 22 is a view in longitudinal cross-section illustrating the methodof assembly,

Fig. 23 is a view in longitudinal cross-section of an alternativeembodiment of the construction shown in Fig. 22,

Fig. 24 shows an alternative embodiment for attaching a sheet metal capto a ceramic projection,

Fig. 25 is a modification of the embodiment oi Fig. 24,

Fig. 26 is a View in longitudinal cross-section illustrating the methodof attaching an electric socket to a ceramic holder,

Fig. 27 is 'a modication of the embodiment of Fig. 26,

Fig. 28 is an elevation View illustrating a iurther modication of theprocess particularly shown in Fig. 26,

Fig. 29 is a diagrammatic View illustrating the process of usingelectrodes for heating and softening and an auxiliary pressure tool ordie ior eiecting the. deformation of the metal,

Figs. 30, 3l and 32 are fragmentary side elevations' of modified formsoi pressure dies or tools for carrying out the method of Figs. 29,

Fig. 33 is a view in longitudinal cross-section illustrating anothermodification oi the general process shown in Fig. 27,

Fig. 34 is a plan view of a metal terminal or 111g,

Fig. 35 is a longitudinal cross-.sectional view thereof, y

Fig.` 36 is a fragmentary view of a ceramic holder to which the terminalof Fig. 38 isto be aixed,

Fig. 37 is a side View illustrating another application of theinvention,

Fig. 38 is a view in longitudinal cross-section illustrating the productproduced by the arrange- ,ment of Fig. 37, and

Fig. 39 is a fragmentary plan view thereof. Referring now to Figs.`l and2, there is shown a method for securing an angle piece W to a' ceramiccarrier. The latter may be provided with a tenen-shaped projection Vupon which one flank of the angle piece is superposed as shown in Fig.l. The two electrodes E and E2 with their electric conductors L' and ll2are so disposed upon the sheet metal piece that the heating occurs inthe length oi' metal therebetween which is carried on to such extentthat the same softens. As a consequence the metal may be drawn about theprojection V to form a cap thereover as best shown in Fig. 2. As themetal then cools it contracts to a greater extent than the ceramiccarrier which has been heated relatively slightly in the operation, andas a conse uence of that contraction the sheet metal cap awstightly'about the ceramic projection to aiford an extraordinarily secureand tight seat thereupon.

sions i3, M in the carrier.

aaoaioo In this connection it is to be, noted that in this process noriveting or the like is required but only the drawing of the materialover the projection `on the ceramic carrier and the resultant shrinkingof the sheet metal part that has been softened in the operationaccomplishes the secure attachment.

Referring to Fig. 3, the insulating carrier l is shown with a flatprojection tapering slightly to its upper face and the metallic sheet 3Which initially is fiat is secured by resort to the electrodes E.

in Fig. 4 an arrangement is shown similarto Figs. 1 and 2 but in thiscase the iiat electrodes E are shaped or formed as tools to press theiiat sheet metal about the tenori-shaped projection 2.

In Fig. 5 the electrodes e are in the form of rollers which areparticularly useful Where the metal part f3 is of considerable Width andthe tenon-shaped projection 2 of corresponding length.

In Fig. 6 the attachment of the metal strip b to a support with anordinary rather than a tenon-shaped projection 2 is also accomplishedwith roller-shaped electrodes e with the addition of a pressure rollerW, which in combination with the two electrode rollers serves to securethe strip to the carrier The pressure roll is' especially advantageouswhere the metal strip is to be securely rolled upon the carrier with theelimination of any open space therebetween. The pressure roll may have asuitable proile according to the cross-sectional form or vthe projectionto which the metal strip is to be attached.

Fig. 7 for instance shows a shape oi roller1 profile for a peakprojection and Fig. 8 a similar roller to be used for attaching themetal to a v rounded projection.

`Where the projection oi the carrier i has a eircular cross-section, oneof the electrodes may be formed in the shape of a ring R as shown inFig. 9 which in the application edects the positioning of the strip dagainst the projection 2 during softening of the material when theelectrode E is applied centrally of the projection to form* the assemblyshown in Fig. lil.

As shown in Figs. 1i, i2 and i3, the application of the metal strip tlupon a circular projection 2 of the carrier may be eected by the use oftwo opposed semi-cylindrical electrodes E.

The surface of the ceramic carrier to which the `sheet metal is to beapplied, may be of any suitable roughened form, for instance with sharpyribs il as shown in Figs. la andV l5, or with rectangular ribs B2 as inFigs. 16 and 17. As shown in Fig. l5 the sharp teeth roughening may bein the form' of corrugations extending transversely across all or'partof the width oi the attachment surface and as illustrativeiy shown inFig. i7,`

the roughened areas may be arranged in the form of lccmcentric circularconformations. it is understood that in the use .of embodiments such asFigs. i4 to 17 the metal parts may be secured to the carrier by means ofpressure stamping dies which have depressions complementary to theprojections shown.

llnFig. 18 is shown an embodiment in which themetal part d is shownsecured to the carrier Il at a projection 2 formed by grooves or depres-Such grooves H3 'and id could also be formed in the interior of a holloWcylinder to be lined with sheet metal.

lin order to avoid loss oi heat in that' part of the metal piece whichis to he shaped by the application of heat, it is desirable, as shown inFigs. 19 and 20 to form slots I6 and I'I which materially minimizes theloss of vheat from the bridging part I8 defined thereby. The speed withwhich this part may be brought to the required plastic condition ismaterially increased yin this manner and metal pieces thus prepared maybe more rapidly assembled, with economy of labor and electric power.

As shownA in Figs. 21 and 22, .the projection to which thev metal part2| is to be attached may be formed as a cylinder. The cylindricalprojection 2 for that purpose is provided at'its periphery withdepressions I9, which extend partially or wholly about the same. Toattain rapid heating of the material, at the part to be pressed inwardit is desirable to perform the shaping in the manner shown in FigiI 21where` the two electrodes E are disposed in closely contiguous relationin the region of the grooves or depressions but with suflicient spacetherebetween for the introduction of a pressure'die 20 at the softenedpart, which serves to press the material into the depression I9. As arule it will not be necessary to press the metal part 2| at its entireperiphery into the depression I9, but normally it will suiiice if thematerial is so depressed into two diametrically opposed parts of thedepression I9.

In Fig. 23 the depressions 22 ,are so disposed that the rim of the metalpart 23 may be bent v thereinto and thereby secure the metal part 23 tothe projection 2.

' In place of rod-shaped electrodes e, roller electrodes of suitableprofile may be'utilized, par. vticularly in such cases where theprojection 2 is circular in cross-section and has annular depressions33, 34 as shown for instance in Figs. 24 and 25. In such cases theelectrodes e may be passed around the periphery of the metal part 24 or25 which is also of circular shape. In the embodiments according toFigs. 21 to 25, 'a normal or a metal glazing or nishing may befintroduced. In the casefof the temperatures attained in this operationthe glazing will melt and pass into intimate engagement between the twoparts to be connected so that a 'gas or fluidtight closure is attained eIn Fig. 26 is shown a carrier I which hastwo projections 2 to which themetal part 26 is attached with the use of two pairs of electrodes E.

Projections 2 are circular in -cross-section and correspond with theembodiment shown in Figs. 11 to 13. The electrodes `in Fig. 26 aresemicircular in cross-section so that-in this manner the attachment ofthe' metal part 2 6 illustratively shown .in ,the form of a lamp socketmay be attained in the same manner as shown in Figs. 11 to 13. e

Fig. 27 shows a carrier I with a projection 2, circular incross-section, to which in addition to the metallic part 2'! there issimultaneously attached another flat metal part 28. Where illustrativelythe part 2l represents an .electric socket, part 28 may constitute ametallic conductor which leads the electric current -to the socket. Bothparts 21 and 28 in the embodiment of Fig. l27 are simultaneouslyattached to the projection 2 by aid of the semi-cylindrical electrodesE.

In order to accelerate the assembly process and thereby save timeand'power, it is possible,

as shown'for instance in Fig. 28 to'previously form the metallic part 29roughly to the shape desired, in a purely mechanical manner as shown at30, which parts are Asuperposed over the projections 2 before theelectrodes are applied, in

order to eiiect accurate and nal attachment of the metal part 29 to thecarrier I.

As shown in Figs. 6 and 7, and 21 and 22, the electrodes maybe utilizedsolely for heating and softening the metal parts while special dies or Qstamps or pressure rolls serve to press the matoothed serrated contourand Fig. 32 a rectangular-toothed serrated contour.

' If it is desired to aiix the metal part to a body which has onlyslight heat conductivity, it is preferable to protect this body orcarrier from excessive heating by means of an, interlay as shown in Fig.l33. The carrier I here has a projection 2 over which extends `theinsulating interlay 35, illustratively made of asbestos and 36 is themetallic piece which is attached to the projection 2 is a singleoperation with the sheetA 35, by use of theelectrodes E.

In Figs. 34, 35 and 36 is shown another embodiment for attachment of themetal piece 3'I upon the carrierI with the cylindrical projection 2. Inthis case the ceramic part is covered by means of a silver plating 38.The aperture 39 provided in the metal part 3l is desirably of diametersmaller than that of the projection 2. The application of the metal part31 is preferably eiected by aid of two opposed semicylindricalelectrodes as shown in a number of the previous embodiments includingfor instance Fig-13. The portion of lthe metal part 3l adjacent theaperture 39 is rolled upward in this operation and in the subsequentcontraction becomes particularly tightly lodged against the projection2.

. "Since a body made of artificial resin or similar materials may bedeformed under certain heat applications, that property may be utilizedin the application of the metal parts. This is illustrated in Figs. 37,38 and 39 where the electrodes E are of conical format their pressureends. Thereby they press corresponding tangs 4I), 4I out of the metalpart into the carrier I. Between the tangs 40, 4I there is thus formed aprojection '2. f

,Having thus described my invention, what I -claim as new' and desire tosecure 'by Letters Patent isz" 1. The method of attaching a flat lsheetmetal plate to a ceramic carrier which comprises conforming the carrierwith one or more surface irregularities, in its otherwise flat face,superposingthe plate thereover, 'applying electrodes to said plate nearthe boundaries of the area dened by said irregularities, thereby tocause thesaid sheet metal member between said electrodes to becomesoftened under the heat of the applied current and concurrently withsaid operation pressing said sheet metal member through said electrodesagainst said insulating carrier and applying pressure through anauxiliary pressure tool to said sheet metal member throughout the regionbetween the electrodes, thereby to cause .the softened sheet metal to beconformed to the -plate to a ceramic carrier provided with a tenonshapedprojection which consists in superposing the metal over the projection,applying electrodes near the opposite edges of the projection thereby tocause the metal between said electrodes to become softened under heatand 'sucking the thus softened material inward about beth sides of theprojection by corresponding portions of "the electrodes, while exertingpressure over the entire area of the upper face of the projection bymeans or a pressure tool interposed between the electrodes.

5. The method of attaching a nat metal plate to an insulating carrierprovided with one or more generally circular mounting studs, whichmethod consists in superposing the metal over the mounting studs,applying semi-cylindrical electrodes to the metal adjacent said studsand causing the disc-shaped portion of the metal bounded by saidelectrodes to become softened and conformed under pressure snugly toengage and encase the studs on the carrier plates'.

6. The method of applying a sheet metal member to a ceramic carrierwhich consists in glazing the latter with a coating of low meltingpoint, applying electrodes to the sheet metal member to cause the sameas well as the glazing to become softened under heat, and shaping thesoftened metal to the conformation of the carrier, whereby in thesubsequent cooling the softened glazing willll in minute voids betweenthe sheet metal piece and its carrier, to aiord a liquid and gas-tightbond therebetween.

7. The method of attaching an electric socket shell to a ceramic carrierprovided with one or :more unitary cylindrical mounting studs, whichconsists in applying electrodes into the socket, one pair for eachmounting stud, thereby causing the region defined by each pair ofelectrodes to be softened under the consequent heat and pressing thethus softened material about the stud or studs.

8. An assembly including a ceramic base and a sheet metal piece rmlybonded thereto, said ceramic base comprising a substantially at facewith a tenori-shaped projection integral therewith, the metal elementengaging said base and being heat shrunk about the tenori for snuggripping thereof.

WERNER OSENBERG.

